I don't think carbon monoxide (from car exhaust), or carbon dioxide (from breath) is the active ingredient.
Low-pressure wind, e.g. from breath (if you can maintain long enough), or a hair dryer at its lowest heat setting, creates a slight vacuum above the epoxy or varnish, so that the bubbles pop from internal pressure. The same principle (called Bernoulli effect) lifts airplane wings. Also used in venturi to create vacuum in carburetors and other applications. Leaf blowers can create a similar phenomenon.
Of course truth is stranger than fiction.
Fiction has to make sense. - Mark Twain